High power demountable electron tube



oct. 3o, 1934. L. A. GEBH'ARD 1,978,424

HIGH POWER DEMOUNTABLE ELECTRON TUBE Filed March 14, 1933 2 Sheets-Sheet1 INVEN TOR.

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Oct. 30, 1934. v L, A. GEBHARD 1,978,424

HGH POWER DEMOUNTABLE ELECTRON TUBE Filed March 14, 1933 2 Sheets-Sheet2 Patented Oct. 30, 1934 UNITED rSTATES 1,978,424 .PATENT ori-lcsl HIGH"POWER DEMOUNTABLE ELECTRON v TUBE vvmuis A. Gebhard, Washington, D. o.Application March 14, 1933, Serial No. 660,708

10 Claims.

have deteriorated, withoutv discarding the entireV tube.

Another object of my invention is to provide a construction of highpower tube having a cylindrical anode provided with means for insuringthe continued cooling of the tube during operation, the coolng meansbeing of such construction that the demountable characteristics of thetube are not impaired.

Still another object of my invention is to provide a simplifiedconstruction of high power demountable electron. tube having an anodewhich forms the envelope of the tube and wherein the anode is providedwith a uid cooling jacket constructed to provide maximum surface contactbetween a cooling medium and the exterior surface of the anode formaintaining the temperature of the anode relatively low under conditionsof continuous operation.

Afurther object of my invention is to provide a construction of,demountable electron tube including a fluid cooled anode structurewherein the exterior surface of the anode structure is provided with aspirally formed heat radiating iin which provides, with a coactingvjacket, a spiral path around the anode for the passage of cooling fluidoperating to dissipate heat due to electronic bombardment of the anodein the demountable tube.

A still further object of my invention is to provide a construction ofhigh powerV electron tube which includes a tubular anode serving as theevacuated envelope for the tube, `and wherein the exterior surface ofthe tubular `anode is provided with a spirally disposed fin extendingbetween iianges formed on the anode and coacting with a surroundingjacket for providinga spiral path for the passage of cooling fluid insurface contact with the exterior of the anode for insuring continuouscooling `of the anode under conditions of electronic bombardment.

Another object ofrny invention is toprovide a compact construction ofhigh power demountable electron tube lin which the envelope for the tubei`s` constituted ,by an anode having fluid cooling passages formedadjacent the exterior surface of the anode for continuously dissipatingheat generated under conditions of electronic bombardment.

Still another object of my invention is to provide a construction ofcylindrical anode for an electron tube in which `the exterior surface ofthe anode is provided with fluid cooled passages (Granted under the actof amended Aprii 30, 1928;

March 3, 1883, as 370 0. G. '757) vwhich are spiralled from oppositeends of the anode to the center thereof for the introduction of coolingfluid adjacent opposite ends of the anode and the discharge of thecooling fluid adjacent the center of the anode for effecting maximumheat dissipation from the anode.

A further object of my invention is to provide a construction of fluidcooled high power demountable tube in which the distribution of coolingfluid in contact with parts of the tube is such that uniform coolingover the entire area of the tube may be obtained for avoiding unequalexpansion of parts with the resulting tendency for loss of vacuum in thedemountable tube.

Other and further objects of my invention reside in the construction ofthe fluid cooled demountable electron tube as set forth moreV fully inthe specification hereinafter following by reference to the accompanyingdrawings, in which:

Figure l is a side elevation ofthe high power tube of my invention withthe tension members, which maintain the parts of the tube in assembledrelation, broken away to more clearly illustrate the tube structure;Fig. 2 is a central vertical longi'tudinal section through the tubetaken on line 2 2 of Fig. lwith certain of the parts illustrated in sideelevation; Fig. 3 is a central vertical longitudinal section through theassembled tube structure taken on line 2 2 of Fig. 1; Fig. 4 is ahorizontal sectional View through the tube structure taken on line 4 4of Fig. 1 and illustrating the discharge port for the cooling fluid;Fig. 5 is a transverse sectional View taken on line 5-5y of Fig. 1 andshowing the arrangement of ports for the introduction of cooling iiuidinto the anode structure; Fig. 6 is a side elevational view of the anodestructure with parts broken away and illustrated in section; Fig. 7 Aisa side elevational view of a modied form of anode structure with partsshown in cross section;

Fig. 8 is a side elevational View of a further modified form of anodestructure for a fluid cooled electron tube constructed in accordancewith my invention; Figs. 9, 10 and 11 illustrate modified forms of gastight joints which may be Vused for insuring a gas tight closurewithinthe tube of my invention; and Fig. 12 illustrates a schematic form ofinsulated turn-buckle device which may be used in compressing the endplates upon the ends of the insulated sleeves which are secured over thetubular anode structure.

The demountable electron tube of my invention employs a replaceablefilament structure where the filament is normally supported inexpansibleV and contractible screw chucks carried in opposite ends ofthe tube which enable a new filament to be introduced in the tube upondisassembly of the tube after the destruction of the filament. Thedetails of the structure by which the filament may be replaced have beenset forth more fully in my copending application Serial No. 660,707,filed March 14, 1933, entitled Demountable electron tube. The closurefor the tube is formed by a cylindrical anode having removable endportions which are normally secured over opposite ends ci the anodeunder compression and the closure maintained air tight and evacuated:from time to time as may be required by any suitable vacuum pump. Thedemountable parts oi the tube are provided with suitable gaskets at thejoints therebetween by which vacuum may be more readily maintainedwithin the chamber formed by the tubular anode. The anode employed inthe tube structure of my invention is tubular in form and has a spirallydisposed fin on the surface thereof extending between flange membersadjacent opposite ends of the anode. A cylindrical sleeve is disposedover the spirally formed fin and coacts therewith to form a fluidcooling passage -for the circulation of cooling fluid around the anode.The fluid may be introduced at the end of the passage adjacent one endof the anode and discharged at a point opposite the other end oi theanode, or the spirals may be oppositely directed toward each other andthe fluids introduced at points adjacent the ends of the spiral passagesformed on the anode and directed toward the center of the anode where itis discharged.

The structure of tube of my invention is highly compact, which is verydesirable in an electron tube system used on high frequencies sincedistributed capacities are thus reduced to a minimum and operationimproved. Good cooling must be present in a demountable vacuum tubeotherwise the temperature of the parts will rise and impair thetightness of the air tight joints.

Referring more particularly to the drawings, the closure for the tube isformed by a tusular anode 2 having a jacket 1 concentrically disposedabout a portion of the anode as will be more fully understood byreference to the drawings. |i'he anode 2 is supported between insulators3 and 3 and end plates 4 and 4. Gaskets are provided at 5 and 5. Thewhole is held together by longitudinal insulating tension members 6. Thefilament is shown at 7, the grid at 8, grid terminal at 8 and outlet tothe vacuum pump at 1. The anode of the tube consists of an innercylindrical member 9 having shoulders l0 and 10 which engage withgaskets 5 and 5. Cut into the surface of 9 are two spiral grooves 11 andl1 starting at the shoulders l0 and 10 respectively and meeting at thecenter. The raised portion or walls 12 and 12 are part of the anodestructure 2. The structure between the shoulders 1G and l0 is enclosedin an outer cylinder 13. A liquid tight joint is made between the endsof 13 and shoulders 10 and 10' by soldering, bracing or welding. Theends 14 and 14 of the anode 2 extend beyond shoulders 10 and 10respectively as described in my copending application. inlets for thecooling liquid are provided at 15 and 15 at the outer ends of the spiralgrooves. An outlet is provided at 16. The spiral grooves are arranged sothat the cool ing liquid as it enters the structure passes around theanode in the same direction, meeting at the center still in the samedirection. The two paths of the liquid combine and pass through theoutlet 16 except for a small portion which passes around the center ofthe anode and through a gap 17, as shown in Fig. 2, between the centralends of the walls 12 and 12. The arrows of Fig. 2 show the path of thecooling liquid. inlets 15 and 15 and 'outlet 16 are fastened to theouter cylinder 13 by soldering, brazing or welding so as to make aliquid tight joint. These inlets and outlets are arranged so that thecooling liquid connections come from the same direction. rihis makes forgreater compactness and ease of connection to the insulating hose coil.The area of the outlet 16 is equal to the sum of the areas of 15 and 15so as to provide uniform liquid now.

The cooling of the anode in this arrangement is very eiicient due to thelarge surface area in contact with the cooling liquid. In addition thereis substantial radiating surface provided by walls 12 and 12. Thesewalls are part of cylindrical member 9 and the heat is readily conductedthrough the metal. The water being a less efcient conductor is allowed agreat area of contact. Thus the amount of heat which can be conductedaway with a safe operating temperature of the cooling liquid and of theanode per inch length of tubes having the same diameter, is greater inthis construction than it is in tubes using just a simple inner cylinderfor a cooling surface. By arranging the cooling liquid to enter thestructure at a point near the air tight joints the tightness of thesejoints is assured. Passing the cooling liquid around the anode in thesaine direction prevents excessive turbulence at the outlet 16. Thispermits greater flow of the cooling liquid for the same pressure drop inthe system or the less pressure drop for the same flow. improved coolingalso ensues due to the reduction of turbulence.

While a preferred form of the arrangement has been described, obviouslycertain modiiications are possible. For instance, a single spiralcovering the full length of the cooling surface of the anode may be usedwith cooling fluid entering at one end and discharging at the other endas shown in Fig. 7. This modification is not as desirable as the onedescribed, in that the air tight joint adjacent to the outlet issubjected to a much higher temperature than that adjacent to the inlet,the cooling liquid being heated in its passage through the tube. Thespiral element which forms the fluid cooling passage in the structure oftube shown in Fig. 7 has been designated by reference character 20. Theinlet for the cooling fluid in this arrangement is shown at 21 while theoutlet is represented at 22. The direction of flow has been representedupwardly. A single continuous spiral with inlets at both ends and anoutlet at the center may be used as shown in Fig. 8, but increasedturbulence will result reducing cooling efficiency. The structure ofFig. 8 has been shown as including the spiral element 23 connected withthe outer surface of anode 14 and coasting with jacket l to form aspiral passage for the cooling fluid which is uniform throughout thelength of the passage. The inlet port 21 provides means for introducingcooling fluid at one end of the spiral passage. The inlet port 24provides means for introducing cooling fluid adjacent the other end ofthe passage. The center discharge port 25 is disposed midway of thespiral passage and provides a discharge means for the cooling iiuidwithout a reduction in the cross sectional area of the cooling fluidpassage and accordingly without increased turbulence which normallyresults in the reduction of the cooling efficiency of the tube. Thisconstitutes a substantial improvement over the spiral arrangement ofpassages illustrated in Fig. 7. Instead of making walls l2 and 12integral with 9, they may be made separate and soldered, braced orwelded to cylindrical member 9. Unless a good joint results, however,the

`the assembly views.

gas tight closure.

`chucks 26 and 27, each of which are fluid cooled by fluid inlet anddischarge connections illus- `trated at 28 for chuck 26 and at 29 forchuck 27.

Throughout the several'assembly views of the tube of myinvention I haveillustrated gaskets at each of the joints which are placed undercompression for preventing the leakage of gas. To simplify theillustration of the invention, these gaskets have been illustratedschematically in However, I desire that it be understood that inpractice the joints are formed with coacting faces establishing aserpentine .course through the joint which substantially preventsundesirable leakage and provides a gas tight seal. Fig. 9 shows endplate 4 provided with an `annular projection 4a which fits into acoacting annular recess 3a in the insulator 3. The gasket 5 which isdisposed therebetween provides a substantial seal against the leakage ofgas.

Fig., 10 shows a modiiied construction in which end plate 4 is providedwith a pair of concentric ribs depending from end plate 4 as illustratedat 4b and 4c. These ribs nt into coacting annular recesses 3b and 3c ininsulator 3. A gasket 5 which is disposed between the ribs and the conacting recessesis deformed out of plane for establishing a gas tightseal. Fig. ll shows a iurther modiiied form of seal in which end plate4. has an annular projection 4d thereon having an echelon or offsetannular face, The insulator 3 l is provided with a coacting face whichis oiset in` steps or echelon formation as represented at 3d. The gasket5 disposed between the echelon faces 4d and 3d serves to prevent seepageof gas between the joints. As I have pointed-out any One `of the'typesof joint illustrated, or any other form of joint may be used forinsuring a gas tight -closure within the anode structure.

It will also be understood that the tension members 6 have beenillustrated schematically for ,the purpose of simplifying theillustration and that in practice I `employ any suitable arrangement oftension adjusting means lfor compressing the end plates 4 and `l againstthe gaskets 5, insulator 3, gaskets 5 vand insulator 3', and One form ofFig. 12 where a turn-buckle of suitable insula- `tion'material 26engages the screw threaded members `2'1 and 28, extending through theend .platesA 4 and 4'. Adjustment of'turn-buckle 25 permits the requiredtension to be placed upon the assembled parts of the tube for `insuringa A suitable tool engaging surface may be providedon the insulatedturn-buckle to enable the turn-buckle to be properly adjusted.

Other forms of tension means may be employed and by the illustration :inFig. 12, I do not intend my invention to belimited to the particularforni of tensioning means shown.v 1

The arrangement of [cooling system for the anode by which iiuid at lowtemperature is in-Y troduced at each end of the anode andthe dischargeuuid which has absorbed heat generated by electronic bombardment and issubsequently dischargedV at the centerof the anode, insures uniformexpansion of parts adjacent opposite ends of the tube and therebyenables a vacuum to be maintained in the tube without excessive loss.

While I have described my invention in one of its preferred embodimentsI desire that it 1-e understood that modifications may be made and thatno limitations upon my invention are intended other than are imposed bythe scope of the appended claims.

The invention herein described may be manufactured and used by or forthe Government the United States of America for governmental purposeswithout the payment of any royalty thereon or therefor.

What I claim as new and desire to secure by Letters Patent ofthe UnitedStates is as follows:

l. A demountable electron tube comprising a cylindrical anode, covermembers for said anode insulatingly mounted at each end thereof, meansfor removably mounting electrodes within said anode and between saidcover members, a spiral'iy disposed continuous strip carried by saidanode, a cylindrical jacket coaxial with said anode with the inner wallthereof connected with the cuter periphery of said strip for forming aspiral passage for cooling iiuid connected with the surface of saidanode.

2. A high power deinountable electron tube comprising a tubular anodehaving an annular flange adjacent each end thereof, an insulated sleevedisposed over each end of said anode adjacent the flanges thereon, endplates extending across said `insulated sleeves, tension membersinterconnecting said end plates for binding said end plates, sleeves andanode under pressure for forming a substantially gas tight chamber,electrodes removably mounted within said chamber,

Vspirally disposed strip formed on the exterior wall of said anodeintermediate said flanges, a jacket concentrically disposed about saidanode and extending over said spirally disposed strip and de fining aspiral passage for cooling iluid around said anode, and fluid inlet anddischarge connections for said jacket.

3.A high power demountable electron tube comprising a tubular anodehaving an annular iange adjacent each'end thereof, insulated sleevevdisposed over each end of said anode adM jacent the iianges thereon,end plates extending across said insulated sleeves,` tension membersinterconnecting said end plates for binding said `end plates, sleevesand, anode .under pressure for 4forming a substantially gas tightchamber, elec trodes removably mounted within'said chamber, a wallmember extending between the flanges on the exterior wall of said anodeand defining a spiral passage along the length of said anode, a

jacket secured over flanges and extending 'f over said wall member andconnected with the peripheral edgesthereof, and fluid inlet anddischarge connect-ions at opposite ends of said jacket for insuring acontinuous circulation cf cooling iiuid over the exterior surface ofsaid anode directly adjacent interior surface thereorn which issubjected to electronic bombardment.

4. A high power deniountable electron tube jacket extending coaxial withsaid anode, the inner wall of said jacket being connected with theperiphery of said strip and defining a spiral passage for cooling fluidalong the length of said anode, a iiuid inlet connection adjacent theflange at one end of said jacket and a fluid discharge connectionadjacent the flange at the opposite end of said jacket.

5. A high power demountable electron tube comprising a tubular anodehaving an annular ange adjacent each end thereof, an insulated sleevedisposed over each end of said anode adjacent the flanges thereon, endplates extending across said insulated sleeves, tension membersinterconnecting said end plates for binding said end plates, sleeves andanode under pressure for forming a substantially gas tight chamber,electrodes removably mounted within said chamber, a strip integrallyconnected with the outer wall of said anode and disposed in a spiralpath between the iianges on said anode, a jacket disposed over saidflanges and over said spiral strip therebetween, fluid inlet connectionsextending into said jacket at opposite ends thereof and ad jacent theflanges thereon, and a iiuid discharge connection disposed substantiallycentral of said jacket for discharging cooling uid passing toward thecenter of said jacket from the inlet connections on opposite endsthereof.

6. A demountable electron tube, a tubular anode, end plates for saidtubular anode, means insulatingly connecting said end plates with theends of asid tubular anode, compression means for maintaining said endplates in assembled relation with said tubular anode, electrodesremovably mounted concentrcally within said tubular anode and betweensaid end plates, an annular flange adjacent each end of said anode, astrip member thermally connected with the exterior wall of said anodeand extending spirally in a clock-wise direction from the flange at oneend of said anode to the center of said anode, a strip member thermallyconnected with the exterior wall of said anode and extending in acounterclock-wise direction from the other of said flanges toward thecenter of said anode and interconnected with the end of the aforesaidstrip, a jacket extending between said flanges and surrounding saidspirally arranged strips, a iiuid inlet connection extending throughsaid jacket adjacent each end thereof for delivering cooling fluid tothe spiral passages surrounding said anode, and a fluid dischargeconnection adjacent the center of said jacket in a position at whichsaid spiral strips meet for discharging cooling fluid from said jacket.

7. A high power demountable tube comprising a tubular anode, a closurefor each end of said anode, electrodes removably mounted within saidclosure concentrically within said anode, a flange connected with theexterior wall of said anode adjacent each end thereof, a jacketextending between said flanges, a member disposed between the inner wallof said jacket and the outer wall of said anode for dening a passagewayfor cooling iuid around said anode, fluid inlet connections for saidjacket adjacent opposite ends of said passageway and a fluid dischargeconnection for said jacket disposed centrally of said passageway.

8. A high power demountable electron tube comprising a cylindricalanode, an annular flange formed on said anode adjacent opposite endsthereof, an insulated sleeve concentrically disposed over each end ofsaid anode and abutting with the annular flange thereon, end platesextending across the ends of said insulated sleeves, means formaintaining said end plates, said sleeves and said anode underlongitudinal compression for providing a substantially gastight chamberwithin said anode, a multiplicity of removable electrodes mounted withinsaid chamber, a jacket disposed concentrically about said anode andconnected with the flanges adjacent the opposite ends thereof, a stripmember thermally united with the exterior surface of said anode andextending in a spiral path between said flanges and connected at itsexterior periphery with said jacket for defining a spiral path aroundsaid anode, iiuid inlet connections adjacent each end of said jacket fordelivering cooling fluid to the spiral path formed about said jacket,and a fluid discharge connection intermediate the length of said jacketfor discharging fluid which circulates through said spiral path fromeach end of said jacket.

9. A high power demountable electron tube comprising a cylindricalanode, an annular flange formed on said anode adjacent opposite endsthereof, an insulated sleeve concentrically disposed over each end ofsaid anode and abutting with the annular flange thereon, end platesextending across the ends of said insulated sleeves, means formaintaining said end plates, said sleeves and said anode underlongitudinal compression for providing a substantially gastight chamberwithin said anode, a multiplicity of removable electrodes mounted withinsaid chamber, a jacket disposed concentrically about said anode andconnected with the flanges adjacent the opposite ends thereof, a stripmember extending in a spiral path from one of said flanges toward thecenter of the tube, a strip member extending from another of saidflanges in a direction opposite to said first mentioned spiral path to aposition intermediate said anode and connected with the other of saidstrip members, a jacket surrounding said strip members and extendingbetween the flan es on said anode, fluid inlet connections at oppositeends of said jacket and a fluid inlet discharge connection centrally ofsaid anode at a'point adjacent the juncture of said strip members.

10. A high power demountable electron tube comprising a tubular anode, aflange adjacent each end of said anode, an insulated sleeveconcentrically disposed about each end of said anode and abutting withthe ange thereon, end plates extending across the ends of said sleeves,tension means interconnecting said end plates for maintaining said endplates, said sleeves and said anode under compression for providing asubstantially gastight closure, a multiplicity of electrodes removablymounted within said closure,

and fluid circulating passages symmetrically dis posed about said anodefor insuring equal cooling of the opposite ends of said anode forequalizing the expansion thereof under conditions of temperature changedue to electronic bombardment.

LOUIS A. GEBHARD.

lei-5

